Users also had difficulties accessing Zune.net, where they can buy music and movies for smartphones, PCs and tablets. The Zune service is also running normally again, according to a status update page for Xbox Live.

Microsoft didn't explain why Xbox Live had gone down and declined to comment on the number of users affected. "Our engineering teams worked quickly to fix the problem and the service is online and fully operational," a Microsoft spokeswoman said in an email.

Xbox Live had about 40 million members as of January, and the service is offered in 35 countries. Microsoft entered the console market with the Xbox in 2001, and introduced the Xbox 360 in 2005.